TBH I don’t think it’s particularly sinister or “Top Secret”, it’s quite obviously a test vehicle/unmanned successor to the Shuttle, a two year in orbit and return mission makes quite good sense if you want to really examine the performance and robustness of systems and vehicles construction…
The shuttle’s longest mission was about 17 days and most agencies tend not to recover satellites, space stations or other orbital kit once they’ve outlived their useful life, so conducting a prolonged orbital test of a bit of kit, then recovering it and being able to thoroughly examine it is quite a big deal for engineers, I doubt they’re publicising the X-37-B’s programme much because of the Shuttles big failures and the scrutiny surrounding it’s safety during it’s final few missions, NASA/USAF are probably quite cautious about the press now…
Two years is nothing, not when you think about how much Unmanned equipment has gone into orbit over the last 30 or so years, much of which the public don’t know the details of…
For the Tinfoil hat brigade, the shuttle took at least eight classified payloads into orbit between 1985 and 1992 for the US DoD, you can only assume those are still up there scanning your brain and irradiating your scrotum from orbit…
